Typically, a seismic data acquisition system comprises a network connected to a central unit.
In a first known implementation, the network comprises a plurality of wired acquisition lines. Each wired acquisition line comprises nodes and concentrators, thus all seismic data can be received in the central unit in a real-time manner. The nodes are assembled in series along a telemetry cable and are each associated with at least one seismic sensor (in general, strings of seismic sensors). These nodes process signals transmitted by the seismic sensor(s) and generate data. The concentrators are assembled in series along the telemetry cable and are each associated with at least one of the nodes. Each concentrator receives the data generated by the node(s) with which it is associated. The sensors are either analog sensors or digital sensors. When analog sensors (also referred to as “geophones”) are used, they are generally interconnected by cables to form clusters referred to as “strings of geophones”. One or several of these strings of geophones (in series or in parallel) are connected to each node (in this case, a node is also referred to as FDU, for “Field Digitizing Unit”) and this latter performs an analog to digital conversion of the signal from the groups of geophones and send these data to the central unit. When digital sensors are used (e.g. micro-machined accelerometers, also referred to as “MEMS-based digital accelerometer”), they are integrated in the nodes (in this case, a node is also referred to as DSU, for “Digital Sensor Unit”), which eliminates the geophone strings. Each node integrates one or several digital sensors.
In a second known implementation, the network comprises wireless seismic acquisition units (also referred to as RAU, for “Remote Acquisition Units”). Each wireless seismic acquisition unit is independent and associated with (i.e. is connected to or integrates one or several functions of) one or several of aforesaid nodes. Each wireless seismic acquisition unit communicates wirelessly (directly or through one or several other wireless seismic acquisition units and/or through one or several of aforesaid concentrators) with the central unit and/or with a harvesting device (carried by an operator also referred to as “harvester”) if a data harvesting strategy is implemented. The set of wireless seismic acquisition units could constitute a multi-hop wireless mesh network, allowing the wireless seismic acquisition units to exchange data, between them and with the central unit. Thus, each wireless seismic acquisition unit stores its own data (i.e. data obtained from the node(s) with which it is associated) and, eventually, also stores data received from one or several other wireless seismic acquisition units (i.e. data obtained from the node(s) associated with this or these other wireless seismic acquisition units). The sensors are either analog sensors or digital sensors. When analog sensors (“geophones”) are used, each wireless seismic acquisition unit integrates for example one or a plurality of aforesaid nodes (as described for the first known implementation with geophones). When digital sensors are used, each wireless seismic acquisition unit is for example connected to a node which integrates one or several digital sensors (as described for the first known implementation with digital sensors).
In the following description, we consider the case of the second known implementation, i.e. a network comprising wireless seismic acquisition units.
In a seismic acquisition survey, the wireless seismic acquisition units are placed on the field at specific locations, known as “topographic locations”. When implementing wireless seismic acquisition units, the following three steps are required (seismic data recording is starting when they are completed):                a) The topographic locations have been defined by a geologist prior to the deployment of the wireless seismic acquisition units. The topographic locations have a precise location on the field (e.g. GPS coordinates or any other GNSS coordinates), which are recorded in a specific file (also called “SPS” file, for “Shell Processing Script” file). The topographic locations are generally computed at a central unit to draw a grid on the ground, along grid lines. In real conditions, there may be thousands of topographic locations on the field. They are indicated (staked out) by surveyors, on the ground, using a marker (stake, flag, paint on the ground, etc.). FIG. 1 illustrates an example of topographic locations 1 on the ground, placed in a grid pattern comprising lines L1-L3.        b) During the seismic mission, the deployment of the wireless seismic acquisition units is performed at all marked topographic locations. In other words, each wireless seismic acquisition unit is installed on the ground, near a marked topographic location. FIG. 2 illustrates an example of wireless seismic acquisition units 2 deployed near marked topographic locations 1, along lines L1-L3.        c) Once wireless seismic acquisition units are deployed, another step is required for their identification on the field. It is necessary to know which wireless seismic acquisition unit is placed at which topographic location. This step is called “assignment step”. An operator needs to walk along the lines where the wireless seismic acquisition units are placed (each line comprises an huge number of wireless seismic acquisition units, each unit being separated to another unit by a planned distance). Next, thanks to the help of an external device 4, the operator 3 records the associations each between one of the wireless seismic acquisition units 2 on the ground and one of the topographic locations 1 (which is close to this wireless seismic acquisition unit). Most of external devices use RFID technology for the identification of units, and so require many people to sweep all the wireless seismic acquisition units with RFID readers. FIG. 3 illustrates a manual assignment by an operator 3 and its external device 4, with the operator walking along a line L3 (as shown by the arrow referenced 5).        
A drawback of this known operation in three steps is that walking along the lines and associating manually the wireless seismic acquisition units with their topographic locations consumes time for the human operators and needs the cost of an external device for each human operator. In other words, the known three-step operation is a huge constraint for deployment of wireless seismic acquisition units. Due to the high volume of wireless seismic acquisition units, it may take several days before starting seismic recording.
Another drawback is that the human operators may make some mistake by manually entering the associations in their external devices.
Yet another drawback is that the human operators are exposed to field hazards while walking on the survey location.